Shacky Trial Evidence

[Pah]

Three highly skilled FBI fingerprint experts declared this year that Oregon lawyer Brandon Mayfield's fingerprint matched a partial print found on a bag in Madrid that contained explosive detonators. U.S. officials called it "absolutely incontrovertible" and a "bingo match." Mayfield was promptly taken into custody as a material witness. Last week the FBI admitted that it goofed; the print actually belongs to Ouhnane Daoud, an Algerian.

Fingerprint evidence has long been considered an infallible form of proof, powerful enough to support a criminal conviction even without any other evidence. But when three top experts manage to blow such an important identification, our longstanding faith in fingerprints must be questioned. Nor is this the only such mistake to come to light in recent months. In January a Massachusetts conviction was overturned when the fingerprint identification, the cornerstone of the case, was shown to be erroneous.

In fact, the science of fingerprinting is surprisingly underdeveloped. We lack good evidence about how often examiners make mistakes, nor is there a consensus about how to determine what counts as a match. Our current approach to fingerprint evidence, in which experts claim 100 percent confidence in any match, is dangerously flawed and risks causing miscarriages of justice.

Fingerprinting, unlike DNA evidence, currently lacks any valid statistical foundation. This is gravely troubling. Even if we assume the unproven hypothesis that each fingerprint is unique when examined at a certain level of detail, the important question is how often two people might have fingerprints sufficiently similar that a competent examiner could believe they came from the same person. This problem is accentuated when analyzing a partial print, as those recovered from crime scenes frequently are. How often might one part of someone's fingerprint strongly resemble part of someone else's print? No good data on this question exist.

Source and complete article-Washington Post

Brandon Mayfield was jailed two weeks ago after a computer identified his prints on a bag of detonators in Spain. But a U.S. judge let him go Thursday after Spanish officials said fingerprints belonging to an Algerian were on the bag.

Fingerprint experts said that if Mayfield was the victim of a fingerprint identification mistake, such errors are likely to become more common with the expanding use of computers that compile police records from around the world into huge, searchable databases.

In theory, no two fingerprints are the same, but some can look similar, according to the Web site of the Scientific Working Group on Friction Ridge Analysis, a group for fingerprint examiners.

No statistics exist on false fingerprint matches in the United States, but mistakes are believed to be rare, in large part because all fingerprints are checked by human examiners who make the final decision on a match

.

Once a computer identifies possible matches, the science of matching is much the same as it was when fingerprints were first used in a U.S. courtroom in Chicago in 1911: It is up to humans to review two blobs of squiggly lines and decide if they are the same.

Spanish authorities first cast doubt on the match, saying they found only eight points of similarity between Mayfield's print and the one on the bag. The FBI said it found 15 coinciding points.

Wertheim said that discussion was perplexing, because fingerprint analysts have largely abandoned the 16-point method of comparing prints after a 1989 British study cast doubt on its reliability.

Source and complete article-PoliceOne.com

Fingerprinting joins eyewitness testimony long recognized as being unreliable in a court of law as being nonconclusive, a part of reasonable doubt,

-pah-

 

[civilcynic]

I remember reading about this but, if I recall correctly, the Spanish authorities also did fingerprinting analysis and did not come to the same conclusion as the FBI did in regards to the fingerprint identification.

Finger identification, DNA, etc; are fallible because human beings are fallible. You can get opposing point of views on any subject or evidence from different experts...the more differing interpretations one has (whether accurate or not), the more confusing and the less likely a person will be arrested or convicted of a crime.

 

[anders]

Not to speak of the so-called "lie detectors". These tests sometimes work and sometimes don't, partly because the cellular stress displays need to be interpreted by trained experts, who in a clinical setting are typically participating in a diagnostic team or at least given access to lots of other information about the person being diagnosed.

If someone tried to sell cancer-detection devices on this basis, they'd get put in jail.

(Partly adapted from a post by an expert phonetician on www.languagelog.org, July 2, 2004.)

 

[Pah]

Not to speak of the so-called "lie detectors". These tests sometimes work and sometimes don't, partly because the cellular stress displays need to be interpreted by trained experts, who in a clinical setting are typically participating in a diagnostic team or at least given access to lots of other information about the person being diagnosed.

If someone tried to sell cancer-detection devices on this basis, they'd get put in jail.

(Partly adapted from a post by an expert phonetician on www.languagelog.org, July 2, 2004.)

I also understand, albeit by way of TV shows and movies, that people can be trained to "beat" the machine itself. The tests actually not allowed in our criminal cases as a prosecution "witness".

-pah-